fesspark Posted October 31, 2014 Share Posted October 31, 2014 I have 2x 90a leisure batteries and a 130 watt solar panel what should the voltage reading be when the vehicle is not in use and no hook up connected. Today it read 14.2 and about 4 hours after I took the hook up off the reading dropped to 13.5 v everything is switched off on the control panel. the batteries are almost new and matching,The sun was shining in the 4 hours after I disconnected the hook up. Is the reading of 13.5 v what I should expect or have I got a battery problem, ? I wish to Know as the batteries are under Guarantee. Link to comment Share on other sites More sharing options...
Guest peter Posted October 31, 2014 Share Posted October 31, 2014 Those battery voltages look bang on for healthy cells to me. You have no problems. Link to comment Share on other sites More sharing options...
Keithl Posted October 31, 2014 Share Posted October 31, 2014 In a nutshell you cannot tell! The 13.5 v you where measuring without hook up is the charging voltage from the solar panel and NOT the 'at rest' voltage of the batteries. You will have to disconnect the solar panel and ideally separate the batteries before allowing them to stand for at least an hour before measuring their voltages with a good digital voltmeter. Then leave to stand for 24 hours and see if the voltage has fallen. The only surefire way to check their actual condition is to do a discharge test, ie run a known load for a known length of time and calculate the percentage of discharge. Only then can you get a true idea of their conditions. Keith. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 1, 2014 Share Posted November 1, 2014 As Keith advises, the solar-panel needs to be removed from the equation. (I guess you could chuck a blanket over the panel if you did not want to disconnect it.) Following Keith’s recommended procedure, when the voltage reading has fallen and stabilised after 24 hours, the relationship between the reading taken then and the batteries’ approximate state of charge will be as shown on the attachment. If the batteries were believed to have been fully charged when the hook-up was disconnected and the solar-panel was disconnected (or ‘masked’) a reading after 24 hours of 12.7volts or higher would be a reasonable indicator that the batteries are in good health. (For accurate readings the batteries must have no electrical load placed on them when the readings are taken and, as Keith emphasises, only a discharge test will offer a true proof of their condition.) Link to comment Share on other sites More sharing options...
Tracker Posted November 1, 2014 Share Posted November 1, 2014 If you disconnect the solar panels be sure to do so before the charge flows through the regulator because some, not all but some, solar regulators can be damaged if they have an input without an output load applied. Link to comment Share on other sites More sharing options...
fesspark Posted November 1, 2014 Author Share Posted November 1, 2014 Thanks for your tip on the Blanket, Do I use the wifes with her in it or mine without. / ha ha Link to comment Share on other sites More sharing options...
Tracker Posted November 1, 2014 Share Posted November 1, 2014 fesspark - 2014-11-01 4:34 PM Thanks for your tip on the Blanket, Do I use the wifes with her in it or mine without. / ha ha The thicker the better! Try your favourite sleeping bag! Link to comment Share on other sites More sharing options...
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